The present invention is directed to a wiper seal for a hydraulic component. More particularly, the present invention is directed to a wiper seal for a rod in a hydraulic component.
Many work machines, such as tractors, excavators, loaders, and other earth moving equipment, utilize hydraulic components to generate the force required to accomplish their tasks. These hydraulic components, which include, for example, hydraulic actuators, hydraulic cylinders, and fluid motors, typically include two fluid chambers disposed on opposite sides of a moveable element. Pressurized fluid is introduced into one of the fluid chambers, which causes the moveable element to move relative to the hydraulic component housing.
The moveable element is usually connected to a work implement on the work machine through a rod or shaft. Typically, each hydraulic component includes a sealing arrangement that prevents pressurized fluid from leaking from the fluid chambers of the hydraulic component during use. One such sealing arrangement for a hydraulic cylinder is described in U.S. Pat. No. 6,116,613.
A sealing arrangement for a hydraulic component may include a series of seals. In one such sealing arrangement for a hydraulic cylinder, three seals are disposed in the cylinder head to engage the shaft proximate the exit point of the shaft. The cylinder head typically includes a series of annular grooves, or counter bores, that are configured to receive each of the three seals. The first seal, which is placed closest to the pressurized fluid, is known as a buffer seal. The buffer seal forms a high pressure seal with the shaft to prevent the pressurized fluid from escaping the hydraulic cylinder. Due to the high operating pressures of the hydraulic cylinders, however, some of the pressurized fluid will leak through the buffer seal.
The second seal, which is placed on the opposite side of the buffer seal from the fluid chamber is known as a xe2x80x9cU-cupxe2x80x9d seal. This seal typically has a notch or groove that forms a xe2x80x9cUxe2x80x9d shape. This seal provides a second barrier to prevent the fluid that has leaked through the buffer seal from escaping the hydraulic cylinder. This fluid is captured in a gap between the buffer seal and the xe2x80x9cU-cupxe2x80x9d seal and in the notch or groove in the seal. When operating conditions permit, the buffer seal allows the captured fluid to bypass the buffer seal and return to the system.
The third seal, or the outermost seal, is known as a wiper seal or, alternatively, as a rod seal or a rod scraper seal. The wiper seal typically includes a lip that forms a seal with the surface of the shaft to prevent dirt or debris from entering the system and contaminating the fluid. Under certain operating conditions, however, fluid may leak through the U-cup seal and collect in the area between the wiper seal and the U-cup seal. The dirt preventative seal formed by the engagement of the wiper seal lip with the surface of the shaft may not effectively prevent the fluid that collects between the wiper seal and the U-cup seal from leaking past the wiper seal and out of the housing.
When fluid leaks from the hydraulic component, the amount of maintenance required by the hydraulic component may be increased. For example, the lost fluid will have to be replaced. In addition, the fluid that leaks out of the housing may adhere to the surface of the shaft. The presence of fluid on the shaft may increase the amount of dirt and debris that adheres to the surface of the shaft, which may increase the possibility of system contamination.
The wiper seal of the present invention is directed to solving all or some of the problems set forth above.
One aspect of the invention is directed to a wiper seal for a hydraulic component. The wiper seal includes a support member that has a first leg with an inner surface, a first end, and a second end and that extends substantially parallel to a reference axis. The support member includes a second leg having an outer surface that extends substantially perpendicular to the reference axis from the first end of the first leg. The wiper seal also includes a body portion defining an opening therethrough. The body portion includes an outer peripheral surface configured to receive the inner surface of the first leg of the support member. A first radial face extends substantially coplanar with the outer surface of the second leg. A second radial face extends generally perpendicular to the reference axis from the second end of the first leg of the support member and includes a cutout defining a first cavity. An inner surface defines a first sealing lip that is adjacent the first radial face. A projection extends from the inner surface to a second sealing lip. The second sealing lip is separated from the first sealing lip by a second cavity.
According to another aspect, the present invention is directed to a hydraulic component that includes a housing defining at least one chamber configured to hold a pressurized fluid. The housing has a head defining an opening. A rod having a surface is disposed in the opening of the housing. A wiper seal is disposed in the housing and includes a support member that has a first leg with an inner surface, a first end, and a second end and that extends substantially parallel to a reference axis. The support member includes a second leg having an outer surface that extends substantially perpendicular to the reference axis from the first end of the first leg. The wiper seal also includes a body portion defining an opening therethrough. The body portion includes an outer peripheral surface configured to receive the inner surface of the first leg of the support member. A first radial face extends substantially coplanar with the outer surface of the second leg. A second radial face extends generally perpendicular to the reference axis from the second end of the first leg of the support member and includes a cutout defining a first cavity. An inner surface defines a first sealing lip that is adjacent the first radial face. A projection extends from the inner surface to a second sealing lip. The second sealing lip is separated from the first sealing lip by a second cavity.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.